Although it can be used to produce a wide range of fiber composite scrims and fiber composite components in various applications, the present disclosure and the problems on which it is based are described in greater detail in relation to the production of curved supporting or secondary aircraft structures, in particular annular formers or annular former segments or other complex curved profiles.
In modern aircraft construction, supporting or structurally reinforcing components are increasingly being made of fiber composite materials such as carbon-fiber-reinforced plastics material (CFRP). For example, a typical aircraft fuselage is subdivided in the longitudinal direction into a plurality of barrel-shaped fuselage segments, which each comprise annularly curved formers extending in the circumferential direction. The formers may in turn be composed of annular former segments. Producing such curved components of large dimensions from composite materials can be a challenge in view of the complex shapes. So, for example when CFRP components are produced, a profile comprising pre-impregnated fibers, fiber strips and/or fibers bands, which is curved to some extent in a radial direction, may need to be rolled up. Different extensions of the profile in a radially internal region and a radially external region can be compensated for by a corresponding curved arrangement of the fibers, in such a way that folds, overlaps or gaps in the laid fiber scrim are prevented.
A widespread fully automated manufacturing process for composite components of this type is automated fiber placement (AFP), in which fiber-reinforced bands are laid, with or without a plastics material matrix or other materials, along a predetermined path on a tool surface using pressure and heat, by a laying head which may be robotically guided. A device of this type is disclosed for example in EP 2 036 702 B1. Typically, a laying head of this type comprises a laying roller, by which one or more fiber composite bands are unrolled continuously onto a laying surface whilst applying pressure and heat, and optionally cut to length at predetermined end points using a cutting tool. A cutting tool of this type is often arranged in the region of the laying roller, in particular above it with respect to the laying surface. The distance of the cutting tool from the laying point thus determines a minimum cutting length of the end piece of the fiber composite band with respect to the laying point.
The fiber composite bands may be laid in the laying surface so as to be straight or curved. If they are laid so as to be curved, the fiber composite material may be orientated in a predetermined orientation, for example under the pressure of the laying roller and the material tension. If the fiber composite band is cut to length using the cutting tool in this case, the material tension in the as yet unlaid end piece of the fiber composite band can cease to be applied over a length corresponding to the minimum cutting length. So as to prevent deviations from the predetermined web guidance and irregularities in the laid fiber material, the fiber composite bands are sometimes deliberately laid past the actual end region and cut to length so as to protrude. Resulting excess material can subsequently be cut off.